Parameters

Return value

If the function fails, the return value is zero. To get extended error information, call
GetLastError.

Remarks

The
ReleaseMutex function fails if the calling thread does not own the mutex object.

A thread obtains ownership of a mutex either by creating it with the bInitialOwner parameter set to TRUE or by specifying its handle in a call to one of the
wait functions. When the thread no longer needs to own the mutex object, it calls the
ReleaseMutex function so that another thread can acquire ownership.

A thread can specify a mutex that it already owns in a call to one of the wait functions without blocking its execution. This prevents a thread from deadlocking itself while waiting for a mutex that it already owns. However, to release its ownership, the thread must call
ReleaseMutex one time for each time that it obtained ownership (either through CreateMutex or a wait function).